Question: What do the following two equations represent? $5x+5y = -5$ $-5x-5y = 5$
Answer: Putting the first equation in $y = mx + b$ form gives: $5x+5y = -5$ $5y = -5x-5$ $y = -1x - 1$ Putting the second equation in $y = mx + b$ form gives: $-5x-5y = 5$ $-5y = 5x+5$ $y = -1x - 1$ The above equations turn into the same equation, so they represent equal lines.